Cooling material from a kiln

ABSTRACT

A method and mechanism for cooling granulate material which includes heating the material in a kiln and directing the material from a kiln into an upper inlet opening of a vertical cooling chamber with the material passing downwardly to flow out of a lower material discharge opening from the cooling chamber, and drawing air from the outside through the material at the discharge opening and forcing said air by an air pump into the material within the cooling chamber with the air flowing upwardly and passing into the kiln. A portion of the air directed into the material also flows downwardly to be recirculated.

United States Patent 1191 Deussner 1 1 COOLING MATERIAL FROM A KILN [75] Inventor: Herbert Deussner,

Bensberg-Refrath, Germany [73] Assignee: Klockner-Humboldt Deutz Aktiengesellschaft [22] Filed: May 3, 1973 [21] Appl. No.: 356,952

[30] Foreign Application Priority Data [111 3,815,253 June 11, 1974 FOREIGN PATENTS OR APPLICATIONS 378,364 7/1923 Germany 432/78 Primary Examiner-.1ohn .1. Camby Attorney, Agent, or Firm-Hil1, Gross, Simpson, Van Santen, Steadman, Chiara & Simpson 5 7] ABSTRACT A method and mechanism for cooling granulate material which includes heating the material in a kiln and directing the material from a kiln into an upper inlet opening of a vertical cooling chamber with the material passing downwardly to flow out of a lower material discharge opening from the cooling chamber, and drawing air from the outside through the material at the discharge opening and forcing said air by an air pump into the material within the cooling chamber with the air flowing upwardly and passing into the kiln. A portion of the air directed into the material also flows downwardly to be recirculated.

17 Claims, 4 Drawing Figures SHEET 1D? 2 FIG.1

COOLING MATERIAL FROM A KILN BACKGROUND OF THE INVENTION The invention relates to a method and mechanism for the cooling of granulate material which is heated in a kiln by direct contact with cooling air. More particularly, the material ishcated in a kiln and discharged into a cooling chamber wherein cooling air is circulated in a unique manner for improved cooling and sealing of the cooling chamber.

Various industrial processes utilize the cooling of material after it has been heated in a kiln wherein the material is in lump form, granulate form or pulverulent form. An example of these processes are fired line items such as dolomite or magnesite. It has been known in the past to direct cooling air through such material in a direction'countercurrent to material flow. How ever, because of the relatively high resistance provided by the hot bulk material to the flow of air, the air must be introduced under substantial pressure. It has been necessary and usual to provide certain types of air seals to prevent the undesirable escape of air in the area where the material is being discharged. To provide such sealing devices has heretofore been complicated and expensive and not wholly satisfactory.

It is accordingly an object of the present invention to provide an improved cooling chamber for cooling particulate materials such as received from a heat treating kiln wherein the necessity of providing sealing equipment for prevention of the escape of cooling air is eliminated.

A further object of the invention is to provide an improved cooling chamber with a unique flow of cooling air that achieves advantages over structures heretofore available.

In accordance with the method and structure of the present invention, the material to be cooled is introduced in the upper end of a vertical cooling chamber and discharged at the lower end with cooling air introduced into the material above the discharge end. A part of the introduced air flows upwardly counter-current t0 the flow of material being cooled. This air flows into the kiln to take advantage of the heat energy contained in the air. Another part of the air introduced into the material is drawn downwardly and recirculated. The air is directed into the material with a power blower, and the intake of the blower draws cool air across the material being discharged from the cooling chamber and draws in a portion of the air being drawn downwardly through the material being cooled. The air entering through the. material discharge mixes with the air being drawn downwardly and provides an effective seal preventing the escape of air into the atmosphere.

In accordance with the features of the invention, the sealing air is introduced into the granulate material to be cooled and is sucked out of the cooling chamber directly in the area of the discharge end. This withdrawal of the cooling air prevents the escape of the air into the atmosphere and. functions in a continual operating cycle which is independent upon the changing flow resistance of the material to be cooled. By guiding the cooling air up through the material as it is discharged,

and directing the main bulk of air passing up through the material into the kiln, the necessity of providing a separate dust removal unit for the air is eliminated.

Further, in accordance with the principles of the structure and method, the quantity of the cooling air can be regulated to be maintained uniform in accordance with a predetermined pressure at the entry into the cooling chamber. By maintaining this pressure at a predetermined level, pressure drop may be maintained into the kiln so that the flow of air into the kiln is assured and no hot dust can escape into the surrounding atmosphere. This also makes it possible to control the entry of external air.

It is accordingly an object of the present invention to provide a cooling chamber for receiving heated materials from a kiln and controlling the quantity of'cooling air introduced into theparticulate material soas to regulate the flow toward the discharge end and the flow of outside air entering to thereby control the effective seal at the material discharge of the cooling chamber.

A further feature of the invention is to control the level of material in the cooling chamber so that a uniform flow of material through the cooling chamber is insured and so that the supply of heated combustion air which flows from the'cooling chamber into the kiln can be regulated forthe uniform operation of the kiln with respect to temperature and quantity. i

A further object of the invention. is to provide an improved relationship between the mechanism for removal of material from the kiln and the flow of cooling air into the material in the kiln for improved cooling and improved sealing effects.

Other objects, advantages and features, as well as equivalent mechanisms and methods which are intended to be covered herein, will become more apparent with the teaching of the principles of the invention in connection with the disclosure of the preferred embodiments in the specification, claims and drawings, in

which:

DESCRIPTION OF THE DRAWINGS FIG. 1 is a somewhat schematic vertical sectional view of a kiln cooling chamber constructed and operating in accordance with the principles of the present invention;

FIG. 2 is a fragmentary diagrammatic. vertical sectional view of a modified form of the invention;

FIG. 3 is a fragmentary schematic modified form of the invention; and

FIG. 4 is a schematic vertical sectional view of a modified form of the invention.

DESCRIPTION FIG. 1 shows a structure wherein a vertical cooling chamber 1 is provided having an upper inlet or material opening 1a and a lower material discharge outlet lb. The structure is arranged so that the discharge from a rotary kiln 9 passes into the upper end of the cooling chamber 1. The kiln is shown schematically with a combustion heater element 9a for heating the material and for utilizing air which is directed to the kiln from the upper end of the cooling chamber 1.

The cooled material discharges from the opening lb at the lower end with the rate of discharge being controlled by a-rotatable horizontal plate 2. The plate is driven in rotation by a motor 20 which is controllable in speed to control the rate at which the particulate or granular material M within the cooling chamber cascades over the edge of the plate. The lower end of the cooling chamber 1 is provided with an annular air suction hood 5. The cooling chamber 1 may be cylindrical in form or of some, other suitable shape, and the hood arranged to have a frusto-conical upper portion and cylindrical lower portion situated so that a discharge gap lb is provided between the edge of the plate 2 and the hood 5.-

An air intake line 6 is connected to the discharge space provided by the hood 5 so that air flows upwardly into the discharge space as indicated by the arrowed lines 10. This continual inward flow of external air sweeps upwardly and mixes with the air passing downwardly through the material as indicated by the arrowed broken lines 11. In other words, the sweep of air into the lower end prevents the escape of the air 11 which has gathered dust and heat in passing downwardly through the material. This effectively provides a zone of subatmospheric air pressure at the material discharge opening due to the suction of the air blower. Any dusty hot air from the material will enter this subatmospheric zone and flow to the pump rather than escaping. I

The cooling air is directed into the cooling chamber through }a distributor 3 which is substantially centrally located within the chamber emerged in the material M.

--The distribution device 3 has suitable air outlet openings so that the air can flow into the material and the major portion of the air flows upwardly as indicated by the arrowed lines 7. This air flows upwardly into the space above the material and into the kiln 9.

Thus, the cooling air is taken into an air intake line 6 and is directed into the material by an air pump means 4 passing through an air discharge line 4b to be discharged by a distributor 3. Because of the drop in pressure between the area of the distributor 3 and the pressure in the suction hood 5, a small part of the cooling air flows downwardly in the direction of material flow, and the combination of this air as indicated by the arrows 11 and the entering air 10 forms an effective gas-dynamic seal. This sealing arrangement provides an additional advantage in that it makes it possible to reduce the structural height of the cooling chamber over devices heretofore available. Both the upward flows of air indicated by the lines 7 and the downward flow. of air 11 perform an effective cooling function on the'granulate material M.

In 'a preferred arrangement, a predetermined pressure is maintained in the upper end of the cooling chamber within the kiln hood 8. For this purpose, a pressure gauge 21 is arranged within the hood 8. The pressure gauge is connected to a transducer 22 which connects to a regulator 23 that regulates the speed of a motor 4a driving the blower 4. The regulator 23 regulates the speed of rotation of the blower 4 to maintain a predetermined pressure as indicated by the gauge 21. Other means may be provided to control the pressure such as by providing a bypass at the discharge of the fan Another preferred arrangement is to maintain the height of the material M within the cooling chamber 1 at a constant level. While the density and resistance to air flow may vary, the maintenance of constant level tends to stabilize conditions withinthe cooling chamber. For maintaining the level uniform, a gauge such as an electric eye 24 may be provided to feed a signal to a transducer 25 which controls a regulator 26 connected to the drive motor 2a for the disk 2. By controlling the speed of the disk, the rate of discharge of material through the hood 5 will be regulated to maintain the predetermined most favorable level of material for a uniform cooling effect.

FIG. 2 illustrates another embodiment wherein a vertical cooling chamber 1 has granulate material M therein. Cooling air is directed into the body of material by an air pump or a blower 4 through an air discharge line 4b leading to a distributor 3 within the ma-. terial. The intake for the pump is provided through an intake line 4a connected to a shielded intake 13 near the bottom of the cooling chamber. At the lower open end lb of the cooling chamber, the granulate material flows downwardly at a controlled rate through a screen 12. This screen may be controlled in size or may be controlled in movement so as to be able to regulate the flow of material to maintain a constant height within the cooling chamber 1. The screen also may consist of spaced parallel rollers which rotate at controlled speeds. Outside cooling air flows upwardly into the lower end of the chamber as indicated by the arrowed lines 10 toenter the intake 13. Theupwardflow of air from the outside prevents the escape of the cooling air which flows downwardly as indicated by the arrowed broken lines 11. Generally, the operation is similar to the arrangement described in connection with FIG. 1, and a kiln, not shown, will be positioned at the top of the cooling chamber 1 to discharge material. 1

In the arrangement of FIG. 2, the cold air 10 which is drawn upwardly from the lower end has a longer flow path through the bulk material, and the cooling is more intensified at the lower end than with the structure of FIG. I. The distance to'the inlet 13 and the crosssectional area of the lower end of the chamber must be so dimensioned that the resistance to air flow to the intake 13 is less than the resistance to air flow downwardly through the bed of granulate material from the distributor 3 to the air intake 13. In the arrangement of FIG. 2, a greater quantity of air will flow downwardly along the lines 11 than along the lines 11 in FIG. 1 resulting in a greater proportion of the air being recirculated through the blower 4. The position of the intake 13 may be adjustable to move downwardly more close to the intake and increase the amount of outside air being drawn in or to move it upwardly to decrease the amount of outside air and increase the amount recirculated downwardly from the distributor 3.

FIG. 3 illustrates another embodiment wherein a primary blower 4 directs air into the interior of granulate material M within a cooling chamber 1. The blower has a direct intake of outside air shown by the arrowed line 4a. A secondary blower 15 directs air into the interior of the cooling chamber through a distributor 14. The secondary blower has an intake 13 at the lower discharge end of the cooling chamber 1. The intake leads to an intake pipe 17 connected to the intake of the blower. The blower discharges through a line 15a with a portion of the discharge passing to a distributor 14 within the material. The principal portion of the air directed to the distributor 14 will flow downwardly as indicated by the arrowed broken lines l4a'to be sucked into the intake 13 along with outside cooling air flowing in as indicated by the arrowed lines 10. The flow of material out of the cooling chamber is controlled by suitable means such as a traveling belt 16 which is driven at a controlled speed.

The discharge from the blower 15 is bypassed in part to be directed up through a line 18 leading to a kiln.

The amount, to be bypassed is controlled by a variable valve 19 in the line 18. The discharge from the line 18 may be also directed to a filter to be discharged into the air. The primary cooling air from the primary blower 4 flows upwardly as indicated by the arrowed lines 3a to preferably pass into the kiln.

In the arrangement illustrated in FIG. 4, a modification of the structure of FIG. 3 is shown. In this modification, the. control of the flow ofmaterial from the cooling chamber 1 is regulated by a vibratory vehicle or gate 20 which is driven in back and forth vibration as indicated bythe arrowed line 200 by an oscillator 20b. A primary blower 4 directs cooling air through a distributor 3 within the mass of particulate material M. A secondary blower withdraws air from the material in part flowing downwardly from the secondary distributor l4 and in part entering through the base of the cooling chamber as indicated by the arrowed line 10.

In the arrangements of FIGS. 3 and 4, the pressure of the sealing airin the zone of the intake 13 is so regulated that it corresponds somewhat to the pressure of the cooling area in the zone of the distributor 3. In this manner, the dynamic gas seal at the base of the cooling chamber is achieved. The pressure control may be obtained by a pressure gauge positioned adjacent the distributor, not shown, and controlling the blower 4 with another. pressure gauge positioned in the area of the distribution device 14 and controlling the blower 15. Control of the pressure of the air being delivered to the distributor 14 may also in part be controlled by variation of the control bypass valve 19.

I claim as my invention:

1. A mechanism for cooling granulate material comprising in combination:

a vertical cooling chamber having an upper material inlet opening and a lower material discharge opening open to atmosphere through which material from the chamber discharges;

an air pump means for supplying cooling air to the material in the chamber;

an air discharge conduit for the air pump having an opening positioned in the interior of the chamber;

and a closed air intake conduit for said air pump means having an intake opening at the lower end of the chamber positioned above said chamber opening to generate a zone of reduced pressure within said opening and positioned for receiving air from said material discharge opening and from the chamber, said air intake conduit supplying the complete supply of air for the pump discharge conduit, said chamber opening being sufficiently large to admit a flow of atmospheric air through the material into said conduit opening. 2. A mechanism'for cooling granulate material constructed in accordance with claim 1:

including a heating kiln connected to said material inlet; and means conducting the cooling air flowing upwardly through the material to the kiln. 3. A mechanism for cooling granulate material constructed in accordance with claim 1:

including means for regulating the rate of flow of material from said material discharge opening. 4. A mechanism for cooling granulate material constructed in accordance with claim 3:

wherein said means for regulating the flow of material includes apower driven rotary disk with the material flowing over the edges of the disk. 5. A mechanism for cooling granulate material con- 5 structed in accordance with claim 1:

wherein said material discharge opening is annular in shape and positioned at the. base of the cooling chamber; means for connecting said air intake to said annular material discharge opening. 6. A mechanism for cooling granulate material constructed in accordance with claim 1:

including means for controlling the height of granulate material in said cooling chamber. 7. A mechanism for cooling granulate material constructed in accordance with claim 6:

wherein said means for controlling the height includes a height sensing means connected to means for regulating the rate of flow through said material discharge opening. 8. A mechanism for cooling granulate material constructed in accordance with claim 1:

including a pressure sensing means at the upper end 25 of said cooling chamber connected to said air pump and regulating the discharge thereof as a function of cooling chamber pressure. 9. A mechanism for cooling granulate material constructed in accordance with claim 1:

wherein a screen is positioned at the material discharge opening for controlling the flow of material from the cooling chamber.

10. A mechanism for cooling granulate material comprising in combination:

a vertical cooling chamber having an upper material inlet opening and a lower material discharge openan air pump means for supplying cooling air to the material in the chamber;

.an air discharge for the air pump leading to the interior of the chamber;

an air intake for said air pump means at the lower end of the chamber positioned below the air intake to generate a zone of reduced pressure within said opening and positioned for receiving air from said material discharge opening and from the chamber;

a kiln for heating material and connected to deliver the material to said material inlet; and means for bypassing a portion of the air from said air pump means to said kiln. 11. A mechanism for cooling granulate material constructed in accordance with claim 1:

including a second air pump means having an air discharge leading to the interior of the chamber. 12. A mechanism for cooling granulate material constructed in accordance with claim}:

whereinthe traveling belt is positioned at the mate rial discharge for carrying cooled material from the cooling chamber discharge. 13. A mechanism for cooling granulate material constructed in accordance with claim I:

and including an inclined vibratory gate for control ling the flow of material from the material discharge opening. 14. A method for cooling granulate material comprising the steps:

recirculated and redirected into the cooling chamber. f l6.A method for cooling'granulate material in accordance with thesteps of claim 14:

including directing the cooling air which flows through the material into akiln positioned to discharge material into the cooling chamber inlet. 17, A method for cooling granulate material in accordance with the steps of claim 14:

including maintaining a predetermined uniform pressure within the cooling chamber. 

1. A mechanism for cooling granulate material comprising in combination: a vertical cooling chamber having an upper material inlet opening and a lower material discharge opening open to atmosphere through which material from the chamber discharges; an air pump means for supplying cooling air to the material in the chamber; an air discharge conduit for the air pump having an opening positioned in the interior of the chamber; and a closed air intake conduit for said air pump means having an intake opening at the lower end of the chamber positioned above said chamber opening to generate a zone of reduced pressure within said opening and positioned for receiving air from said material discharge opening and from the chamber, said air intake conduit supplying the complete supply of air for the pump discharge conduit, said chamber opening being sufficiently large to admit a flow of atmospheric air through the material into said conduit opening.
 2. A mechanism for cooling granulate material constructed in accordance with claim 1: including a heating kiln connected to said material inlet; and means conducting the cooling air flowing upwardly through the material to the kiln.
 3. A mechanism for cooling granulate material constructed in accordance with claim 1: including means for regulating the rate of flow of material from said material discharge opening.
 4. A mechanism for cooling granulate material constructed in accordance with claim 3: wherein said means for regulating the flow of material includes a power driven rotary disk with the material flowing over the edges of the disk.
 5. A mechanism for cooling granulate material constructed in accordance with claim 1: wherein said material discharge opening is annular in shape and positioned at the base of the cooling chamber; means for connecting said air intake to said annular material discharge opening.
 6. A mechanism for cooling granulate material constructed in accordance with claim 1: including means for controlling the height of granulate material in said cooling chamber.
 7. A mechanism for cooling granulate material constructed in accordance with claim 6: wherein said means for controlling the height includes a height sensing means connected to means for regulating the rate of flow through said material discharge opening.
 8. A mechanism for cooling granulate material constructed in accordance with claim 1: including a pressure sensing means at the upper end of said cooling chamber connected to said air pump and regulating the discharge thereof as a function of cooling chamber pressure.
 9. A mechanism for cooling granulate material constructed in accordance with claim 1: wherein a screen is positioned at the material discharge opening for controlling the flow of material from the cooling chamber.
 10. A mechanism for cooling granulate material comprising in combination: a vertical cooling chamber having an upper material inlet opening and a lower material discharge opening; an air pump means for supplying cooling air to the material in the chamber; an air discharge for the air pump leading to the interior of the chamber; an air intake for said air pump means at the lower end of the chamber positioned below the air intake to generate a zone of reduced pressure within said opening and positioned for receiving air from said material discharge opening and from the chamber; a kiln for heating material and connected to deliver the material to said material inlet; and means for bypassing a portion of the air from said air pump means to said kiln.
 11. A mechanism for cooling granulate material constructed in accordance with claim 1: including a second air pump means having an air discharge leading to the interior of the chamber.
 12. A mechanism for cooling granulate material constructed in accordance with claim 1: wherein the traveling belt is positioned at the material discharge for carrying cooled material from the cooling chamber discharge.
 13. A mechanism for cooling granulate material constructed in accordance with claim 1: and including an inclined vibratory gate for controlling the flow of material from the material discharge opening.
 14. A method for cooling granulate material comprising the steps: passing the material through a vertical cooling chamber having a material inlet at the upper end and a material discharge at the lower end, drawing atmospheric cooling air over the material solely through said material discharge and forcing said air into the material within the cooling chamber.
 15. A method for cooling granulate material in accordance with the steps of claim 14: wherein a portion of the air directed into the chamber flows upwardly and a portion flows downwardly with the portion flowing downwardly being recirculated and redirected into the cooling chamber.
 16. A method for cooling granulate material in accordance with the steps of claim 14: including directing the cooling air which flows through the material into a kiln positioned to discharge material into the cooling chamber inlet.
 17. A method for cooling granulate material in accordance with the steps of claim 14: including maintaining a predetermined uniform pressure within the cooling chamber. 